The overall aim of this research is to test two theoretical explanations as to why preparatory sensory/procedural information lessens some patients report of distress following aversive medical/dental treatment. This project will compare the effectiveness of 4 cognitive (information) strategies in attenuating immediate and remembered pain/distress following root canal treatment when individual preferences for personal control are known. Other aims of the study are to compare: 1) The control enhancing effects of the manipulations by examining the discrepancy between the level of control expected and the level of control felt among the experimental groups. 2) The effect of the experimental manipulations on feelings patients report focusing on during an aversive dental event. 3) The level of predictability patients report following root canal treatment among patients given differing types of preparatory information. 4) The measurement of pain and distress using two different techniques (i.e., Verbal Descriptor Scales and Visual Analogue Scales). Researchers believe that procedural/sensory information can significantly reduce the amount of pain and distress some patients experience during aversive medical/dental procedures. Yet the reasons this strategy works for some patients and not for others are not well understood. One explanation involves individual differences in personal control preference; these differences are believed to influence the therapeutic impact of this cognitive control strategy. The conceptualization of personal control, however, that has emerged from past personal control research has emphasized only perceived control (felt) whereas recent work from this project team has studied the desire for control. The added predictive utility of assessing subjects desire for control as well as perceived control has been established through preliminary studies. This project proposes to study "in vivo" the influence of individual differences in the desire for and feelings of personal dental control on distress and pain as well as testing two possible explanations for the differential effectiveness of procedural/sensory information on distress and pain accompanying root canal therapy. Finally, this research has important implications for "informed consent". Data from this investigation will provide theoretical rationale for including certain combinations of sensory and procedural information.